JP3674717B2 - Data recording method and apparatus, data reproduction method and apparatus, data transmission method and apparatus - Google Patents

Description

となる。
【０００９】
ところが実際のデータ発生量Ｅr は、次式
【数２】

に示すように、一定値Ｒ×Ｔにはならない。ここでＢはエンコーダ内に設けられているバツフアメモリの容量である。
【００１０】
このデータをそのまま記録媒体に記録し、その後読み出した場合を考えると、読み出し時間ｔは、次式
【数３】

となる。読み出されたデータはデコーダによつて動画像信号へ復号されるが、復号後の動画像信号の再生時間はやはりＴとなる。このことから画像の再生時間と、それに必要なデータの読み出し時間は異なることが分かる。
【００１１】
ところでＡＶサーバのように、ある一定時間分の動画像信号を圧縮符号化したデータ（以後これをクリツプと呼ぶ）を任意の個数だけ媒体に書き込み、その媒体から任意の個数のクリツプを読み出し、その画像信号を連続再生する場合、以下のような問題点がある。
【００１２】
ある一定時間分の動画像信号を圧縮符号化したクリツプを任意の個数だけ媒体に書き込み、その媒体から任意の個数のクリツプ画像信号を連続再生する場合、必要なデータを読み出す時間がそれぞれ異なるため、データの読み出し時間が再生時間より長くなると、実際のクリツプ画像信号を途切れなく連続再生することができないという問題があつた。
【００１３】
本発明は以上の点を考慮してなされたもので、任意の時間長でなるクリツプ画像を途切れなく再生することができるデータ記録方法及び装置、データ再生方法及び装置、記録媒体、データ伝送方法及び装置を提案しようとするものである。
【００１４】
【課題を解決するための手段】
かかる課題を解決するため本発明においては、ある一定時間分の動画像信号を圧縮符号化後パケツト化したパケツトデータを記録媒体に記録する際又は伝送路に出力する際、パケツトデータの出力開始から一定時間の間はパケツトデータを先入れ先出し方式のバツフアメモリに書き込むだけで記録媒体又は伝送路への読み出しを禁止する。
やがてパケツトデータの出力開始から一定時間が経過した後は、圧縮符号化後パケツト化したパケツトデータを先入れ先出し方式のバツフアメモリへの書き込む一方で先入れ先出し方式のバツフアメモリに書き込まれているパケツトデータを書き込み時以上のデータレートで読み出して記録媒体に記録し、又は伝送路に出力するようにする。
【００１５】
一方、ある一定時間分の動画像信号を圧縮符号化してなる圧縮符号化データが当該圧縮符号化データのデータ発生量に係わらず常に一定サイズのパケツトデータに変換されて記録されている記録媒体からパケツトデータを読み出す際又は伝送路から受信する際、当該パケツトデータを記録媒体に書き込むときのデータレート又は伝送路に出力するときのデータレート以上のデータレートによつて読み出して先入れ先出し方式のバツフアメモリに書き込むようにする。その後、当該先入れ先出し方式のバツフアメモリに既に書き込まれているパケツトデータをパケツト化したときとほぼ同じデータレートで読み出して復号する。
【００１６】
【作用】
通常、動画像信号を圧縮符号化する場合、発生データ量が変動するが、これら変動に係わらず記録媒体に記録される時点又は伝送路に出力される時点における圧縮符号化データは一定サイズのパケツトデータに変換される。従つて発生データ量の多寡によらず一定時間内に動画像信号の記録又は伝送を完了することができる。
一方、再生側又は受信側も発生データ量の多寡によらず一定時間内に動画像信号についての圧縮符号化データを再生又は受信できる。
【００１７】
【実施例】
以下図面について、本発明の一実施例を詳述する。
【００１８】
（１）記録方法及び再生方法の原理
ある一定時間分の動画像を圧縮符号化したデータ、すなわちクリツプを任意の個数だけ記録媒体に書き込み、その記録媒体から任意の個数の画像信号を途切れなく連続再生をするため、この実施例に示す記録装置は、圧縮符号化後パケツト化したデータをＦＩＦＯバツフアメモリに一定時間書き込んだ後、書き込み時以上のデータレートでデータを読み出して記録媒体に記録するようにする。
【００１９】
またこの実施例に示す再生装置は、記録媒体から記録時と同レート又はそれ以上のレートで読み出したパケツトからデータを抽出し、このデータを記録時以上の容量をもつＦＩＦＯバツフアメモリに書き込んだ後、符号時と同じレートで読み出して伸長復号処理するようにする。
【００２０】
（２）基本システム構成
（２−１）記録装置と再生装置の構成
図１にこれら記録方式を実現する記録装置１と、これら読み出し方式を実現する再生装置２のハードウエア構成例を示す。
まず記録装置１の構成を説明する。記録装置１はエンコーダ１Ａ、パケツト化処理部１Ｂ、ＦＩＦＯバツフアメモリ１Ｃ及びパデイングパケツト処理部１Ｄによつて構成されている。
【００２１】
エンコーダ１Ａは圧縮符号化処理部１Ａ１と、エンコードバツフアメモリ１Ａ２の２つによつて構成されている。圧縮符号化処理部１Ａ１は動画像信号Ｓ１を平均レートＲｅで可変量圧縮符号化し、符号化データＳ２を容量Ｂｅのエンコードバツフアメモリ１Ａ２に順次出力するようになされている。
またエンコードバツフアメモリ１Ａ２は符号化データＳ２が一定量メモリ内に蓄積されると、符号化データＳ２をレートＲｅで出力するようになされている。因にエンコードバツフアメモリ１Ａ２のバツフア残量Ｂｅは圧縮符号化処理部１Ａ１にフイードバツクされ、バツフアが破綻しないようになされている。
【００２２】
パケツト処理部１Ｂは、エンコーダ１Ａから出力される符号化データＳ３を順次入力し、これらを１又は複数のパケツト内に格納して出力する。この際、パケツト処理部１Ｂはパケツトサイズやデータの種類、時間情報等必要な情報をパケツトヘツダに書き込み、これを符号化時と同じ一定レートＲｅでＦＩＦＯバツフアメモリ１Ｃに出力するようになされている。
【００２３】
ＦＩＦＯバツフアメモリ１Ｃはデータレートの変換用に設けられた容量Ｂｗのバツフアメモリである。ＦＩＦＯバツフアメモリ１ＣはレートＲｅで書き込まれるパケツトデータＳ４を所定の時間Ｔｗの間蓄積し、その後、書き込み時のレートＲｅより高い読み出しレートＲｗで読み出し、これを記録媒体３に記録するようになされている。
【００２４】
この結果、符号化時の発生情報量の多寡によらず必ずクリツプ時間Ｔに相当する時間内にパケツトデータＳ５を記録媒体３に書き込むことができるようになされている。
因にこの読み出し動作時におけるＦＩＦＯバツフアメモリ１Ｃの蓄積時間Ｔｗ、読み出しレートＲｗ、バツフア容量Ｂｗは、それぞれ以下のように計算される。
【数４】

【数５】

【数６】

【００２５】
因にＦＩＦＯバツフアメモリ１Ｃは、Ｒｗ＞Ｒｅという関係からデータを記録媒体３に書き込む途中で内部のデータがなくなるおそれがあり得る。この事態に備えて設けられているのがパデイングパケツト処理部１Ｄである。
パデイングパケツト処理部１ＤはＦＩＦＯバツフアメモリ１Ｃのバツフア残量Ｂｅを常時検出しており、バツフア残量Ｂｅが０になつたとき、データに直接関係のない無意味なパケツト（すなわちパデイングパケツト）を出力して空白期間に充填するようになされている。これにより伝送形態に破綻が生じないようになされている。
【００２６】
続いて再生装置２の構成を説明する。再生装置２はデータ抽出処理部２Ａ、ＦＩＦＯバツフアメモリ２Ｂ及びデコーダ２Ｃによつて構成されている。
再生装置２は記録媒体３に記録されている記録データを一定レートＲｗで読み出し、これを再生データＳ６としてデータ抽出処理部２Ａに読み込む。
データ抽出処理部２Ａは読み出される再生データＳ６の中からパデイングパケツトを取り除いて破棄すると共に、動画像信号に対応する符号化データＳ７のみを抽出して読み出し用のＦＩＦＯバツフアメモリ２Ｂに送出するようになされている。
【００２７】
このときデータ抽出処理部２Ａが記録媒体３から記録データＳ６を読み出す際の読み出しレートを書き込みレートと同じＲｗとすると、読み出しに必要な時間Ｔｄは、次式
【数７】

となり、常にクリツプの表示時間内に収めることができることが分かる。
【００２８】
このようにデータ抽出処理部２Ａによつて抽出された符号化データＳ７は読み出し用のＦＩＦＯバツフアメモリ２Ｂに書き込まれ、データレートを本来のデータレートに戻される。この読み出し用のＦＩＦＯバツフアメモリ２Ｂの容量Ｂｒは次の条件を満たす。
【００２９】
一般にデコーダ２Ｃに内蔵されているデコードバツフアメモリ２Ｃ１の容量は、エンコードバツフアメモリ１Ａ２の容量以上もつとされているので、本実施例の場合、読み出し用のＦＩＦＯバツフアメモリ２Ｂの容量Ｂｒは、次式
【数８】

に示すように、書き込み用のＦＩＦＯバツフアメモリ１Ｂの容量Ｂｗと同じかそれ以上のものを用る。
【００３０】
最後にデコーダ２Ｃについて説明する。デコーダ２Ｃはデコードバツフアメモリ２Ｃ１と伸張復号化処理部２Ｃ２とによつて構成されている。
デコードバツフアメモリ２Ｃ１はＦＩＦＯバツフアメモリ２Ｂから一定レートＲｅで符号化データＳ８を読み出し、これを伸張復号処理部２Ｃ２に与えるようになされている。伸張復号処理部２Ｃ２は符号化データＳ８を平均復号化レートＲｅによつて復号し、復号結果を動画像信号Ｓ１０として出力する。
【００３１】
（２−２）記録手順及び再生手順
以上の構成において、記録時及び再生時に記録装置１及び再生装置２内で実行される記録動作及び再生動作を順に説明する。
まず複数のクリツプを途切れなく連続再生できるようにすることを想定した記録時の記録動作を図２を用いて説明する。
【００３２】
記録装置１は記録動作が開始されると、ステツプＳＰ１からステツプＳＰ２に移り、動画像信号を記録する記録媒体３上の位置を書き込みポインタによつて指定する。因にこのポインタは再生時に動画像信号の記録データを読み出すための読み出しポインタとして使用される。
書き込みポインタの指定が完了すると、記録装置１の処理はステツプＳＰ３に移り、エンコーダ１Ａに動画像信号Ｓ１が入力され、可変量符号化が開始される。
【００３３】
符号化が開始されると、記録装置１はエンコーダ１Ａによつて動画像信号Ｓ１を平均レートＲｅによつて符号化し、ステツプＳＰ４に示すように、符号化によつて得られた符号化データＳ３を順次パケツト化する。またこれと同時に、記録装置１はパケツト化されたパケツトデータＳ４をＦＩＦＯバツフアメモリ１Ｃに書き込み始める。
記録装置１は、次のステツプＳＰ５に示すように、書き込み開始時刻からの経過時間を確認し、経過時間が（４）式で与えられる蓄積時間Ｔｗより大きいか否か判定する。
【００３４】
やがて肯定結果が得られると、記録装置１はステツプＳＰ６に示すように、ＦＩＦＯバツフアメモリ１ＢからパケツトデータＳ５の読み出しを開始する。この読み出し時におけるデータレートＲｗは前項において説明したように、ＦＩＦＯバツフアメモリ１Ｃに書き込まれる際のデータレートＲｅに比して大きいデータレートである。
【００３５】
この後、ステツプＳＰ７に示すように、ＦＩＦＯバツフアメモリ１Ｃのバツフア残量Ｂｅが０になつたことが確認されるまで、記録装置１はステツプＳＰ７からステツプＳＰ６に戻り、ＦＩＦＯバツフアメモリ１Ｃから読み出したパケツトデータＳ５の記録媒体３への書き込みを継続する。
因にステツプＳＰ７において肯定結果が得られ、ＦＩＦＯバツフアメモリ１Ｃが空になつたことが確認されると、記録装置１はステツプＳＰ８において、ＦＩＦＯバツフアメモリ１ＢへのパケツトデータＳ４の書き込みが全て終了したか否かの判定処理に移る。
【００３６】
このとき否定結果が得られると、記録装置１は読み出しレートＲｗが書き込みレートＲｅに対して大きいために一時的にＦＩＦＯバツフアメモリ１Ｃが空になつたものと判断し、ステツプＳＰ８に移つてパケツトの不足分をパデイングパケツトによつて充填する。
かかる後、記録装置１はステツプＳＰ７に戻つて再度バツフア残量Ｂｅが０か否か判断し、０でない場合には記録媒体３への書き込みを再開し、０である場合には再びステツプＳＰ８においてＦＩＦＯバツフアメモリ１Ｃへの書き込みが終了したか否か判断する。
【００３７】
やがてステツプＳＰ８において肯定結果が得られると、一連の動画像信号Ｓ１の記録終了がステツプＳＰ１０で確認され、次のステツプＳＰ１１において次のクリツプの動画像信号Ｓ１を記録するか否かの判定に移る。
ここで肯定結果が得られている間、記録装置１はステツプＳＰ２〜ステツプＳＰ１１の処理を繰り返し実行する。否定結果が得られたとき、複数のクリツプの記録を終了する。
【００３８】
続いてこのように記録された記録媒体３から記録データを再生する時の再生動作を図３を用いて説明する。
再生装置２は再生動作が開始されると、ステツプＳＰ２１からステツプＳＰ２２に移り、記録データを読み出す記録媒体３上の位置を読み出しポインタによつて指定する。
この読み出しポインタの指定が終了すると、ステツプＳＰ２３に示すように、記録媒体３からの読み出しが開始される。
【００３９】
再生装置２は再生データＳ６をデータ抽出処理部２Ａに読み込むと、ステツプＳＰ２４に示すように、一定レートＲｗで読み出される再生データＳ６からパデイングパケツト等、符号化データと無関係なデータを抽出して取り除く。
その後、再生装置２はステツプＳＰ２５において動画像信号部分の符号化データＳ７をＦＩＦＯバツフアメモリ２Ｂに与える。
続くステツプＳＰ２６に移ると、再生装置２はＦＩＦＯバツフアメモリ２Ｂによつてレート変換した符号化データＳ８をデコーダ２Ｃに与え、このデコーダ２Ｃによつて動画像信号Ｓ１０の再生を開始する。
【００４０】
そして次のステツプＳＰ２８において、再生装置２はデータの読み出しが全て終了したか否か判定し、否定結果が得られている間、ステツプＳＰ２９−ステツプＳＰ２４−ステツプＳＰ２５−ステツプＳＰ２６−ステツプＳＰ２７−ステツプＳＰ２８の処理を繰り返す。
この処理ループを繰り返すことによりクリツプ１つ分のデータ読み出しが終了すると、再生装置２はステツプＳＰ２８からステツプＳＰ２９に移り、連続再生される次のクリツプがあるか否かの判定処理に移る。
【００４１】
ここで肯定結果が得られている間、再生装置２はステツプＳＰ２２〜ステツプＳＰ２８の処理を繰り返し、否定結果が得られた時点でステツプＳＰ３０の処理に移る。
そしてステツプＳＰ３０において、デコードバツフアメモリ２Ｃ１のバツフア残量が０になつたことを確認した時点でステツプＳＰ３１に移り、再生動作を終了するようになされている。
【００４２】
以上の記録再生動作例として２つのクリツプ１及びクリツプ２を連続記録する場合のデータ量と処理時間との関係を表したの図４及び図５である。
まず連続記録されるクリツプ１及びクリツプ２の画像時間はそれぞれ図４（Ａ）に示すようにＴ及びＴ’であるとする。一般に、エンコーダ１Ａのエンコードバツフアメモリ１Ａ２には直前に符号化された画像データが残つているためＦＩＦＯバツフアメモリ１Ｂからクリツプ１及びクリツプ２の符号化データＳ３を読み出すには図４（Ｂ）に示すようにＴ＋ΔＴ及びＴ’＋ΔＴ’の時間がかかる。
【００４３】
この符号化データＳ３を従来のようにそのまま記録媒体３に記録すると、記録媒体３からクリツプ１及びクリツプ２を再生するのに同じくＴ＋ΔＴ及びＴ’＋ΔＴ’の時間が必要となり、表示時間に対して長くなつてしまう。このため従来の再生装置では２つのクリツプ１及びクリツプ２を連続的に再生しても表示時にΔＴの空白時間が生じるおそれがあつた。
【００４４】
これに対して、本実施例に示す記録装置１はＦＩＦＯバツフアメモリ１Ｂから平均符号化レートＲｅより大きいデータレートであり、かつ（５）式を満たす条件でデータを読み出すため、クリツプ１及びクリツプ２を含むデータ部分はいずれもバツフア残量Ｂｅの多寡によらず画像時間Ｔ及びＴ’以内に記録媒体３に書き込みを終了することができる。これを表しているのが図４（Ｃ）である。因に図中斜線で示す時間は、パデイングパケツトが充填される期間である。
記録媒体３には記録終了時、図４（Ｃ）に示すデータ構造でデータが記録されることになる。
【００４５】
一方、再生時、再生装置２は図５（Ａ）に示すようにクリツプ１及びクリツプ２に対応する動画像信号の記録データをそれぞれ時間Ｔ及びＴ’内に読み出すことができる。
しかも読み出された再生データＳ６からパデイングパケツト等、符号化データと無関係なデータが抽出されるため図５（Ｂ）に示すようにＦＩＦＯバツフアメモリ２Ｂに読み出されるデータは真に動画像信号に相当するデータだけになる。
【００４６】
この後、符号化データＳ８は図５（Ｃ）に示すようにＦＩＦＯバツフアメモリ２Ｂからデコーダ２Ｃに元のデータレートＲｅによつて読み出され、復号される。このとき図５（Ｃ）ではバツフア残量分、みかけのデータ読み出し時間がクリツプ１及びクリツプ２の表示時間に対して長くなつているが、各符号化データの復号動作は時間Ｔ及びＴ’で終了するため図５（Ｄ）に示すような２つのクリツプ１及び２の連続再生が可能となる。
【００４７】
以上の構成によれば、連続再生しようとする２つのクリツプの動画像信号を各表示時間Ｔ及びＴ’内に記録媒体３から読み出すことができることにより、復号動作の遅れによるクリツプの表示遅れを回避できる。これにより複数のクリツプを空白期間なく連続して再生できる記録装置１及び再生装置２を実現できる。また連続再生の可能な記録媒体３を実現できる。
【００４８】
（３）応用システム
次にこの基本システムを応用したシステム構成例を示す。ここでは記録装置１、記録媒体３及び再生装置２間がそれぞれ通信回線で接続された一体型のシステムと、記録装置１と記録媒体３との間又は記録媒体３と再生装置２との間が有線路で接続されていな分離型のシステムとについて説明する。
【００４９】
（３−１）一体型システム
ここでは一体型システムの例として、ＡＶ信号（オーデイオ信号及びビデオ信号）を通信回線を介して多数の端末装置に分配するサーバシステム（以下ＡＶサーバシステムという）について説明する。図６にＡＶサーバシステム１１の全体構成を示す。
このＡＶサーバシステム１１はデータ供給源１２、エンコード部１３及びサーバ部１４の３つの部分によつて構成されており、サーバ部１４から多数の端末１５Ａ1 〜１５ＡN にＡＶ信号を分配するのに用いられる。各部は次のように構成されている。
【００５０】
データ供給源１２はビデオテープレコーダ（ＶＴＲ）や光磁気デイスク装置等の再生装置１２Ａで構成されている。各再生装置１２ＡはＡＶデータ信号ＳＤ１、ＳＤ２……を伝送路や信号線を通じてエンコード部１３に供給する。因にこの例ではデータ供給源１２を複数台設けるものとする。
エンコード部１３は基本システムの記録装置１に対応する部分であり、エンコーダ１３Ａ、ＦＩＦＯバツフア／パケツト処理部１３Ｂ及びコントロール部１３Ｃで構成されている。
【００５１】
このうちエンコーダ１３Ａは各データ供給源１２から入力されるＡＶデータ信号ＳＤ１、ＳＤ２……をそれぞれＭＰＥＧ２の規格に従うデータフオーマツトの信号に符号化し、データストリームＤ１、Ｄ２……に変換するようになされている。
ＦＩＦＯバツフア／パケツト処理部１３ＢはこれらデータストリームＤ１、Ｄ２……をそれぞれＦＩＦＯバツフアメモリに一旦記憶してレート変換し、レート変換された符号化データをパケツト処理部でパケツトデータに変換する。
【００５２】
コントロール部１３Ｃはコントロール信号Ｓ_CTL によつてデータ供給源１２、エンコーダ１３Ａ及びサーバ部１４を制御すると共に各部の動作状態を管理するようになされている。
【００５３】
サーバ１４は記録再生部１４Ａ及びデコード部１４Ｂにより構成されている。ここで記録再生部１４Ａは圧縮符号化された符号化データをさらに時間軸方向に圧縮した符号化データを記録媒体に記録するようになされ、ユーザから指示があつたとき対応するＡＶデータを読み出してデコード部１４Ｂに出力するのに用いられる。因にユーザからの指示は要求信号Ｓ_request として入力される。
【００５４】
さて記録再生部１４Ａはメデイア制御部１４Ａ１と複数のメデイアユニツト１４Ａ２〜１４Ａ８とによつて構成されている。ここでメデイア制御部１４Ａ１は複数のメデイアユニツト１４Ａ２〜１４Ａ８の記録再生動作を制御するユニツトである。またメデイアユニツト１４Ａ２〜１４Ａ８はそれぞれ複数のハードデイスク装置を内蔵しており、複数の信号を同時並列的に記録再生できるようになされている。これにより多数の端末１５Ａ１〜１５ＡＮからのマルチアクセスが実現できる。またこれらハードデイスクには連続再生が要求されるクリツプの動画像信号が記録されている。
【００５５】
またデコード部１４Ｂはデータ抽出処理部／ＦＩＦＯバツフアメモリ１４Ｂ０と複数台のデコーダ１４Ｂ１〜１４ＢＭとによつて構成されている。ここでデコード部１４Ｂに用意されるデコーダ１４Ｂ１〜１４ＢＭの数は最終的に接続される端末１５Ａ１〜１５ＡＮの数と、記録再生部１４Ａが同時に再生できる符号化データの数とに応じて定まる。
【００５６】
デコード部１４Ｂは各デコーダ１４Ｂ１〜１４ＢＭによつて各メデイアユニツト１４Ａ２〜１４Ａ８を介して読み出された符号化データを復号し、各端末１５Ａ１〜１５ＡＮに出力する。
因にこのＡＶサーバシステム１１は１つの部屋の中に必ずしも設けられている必要はなく、ＬＡＮ（Local Area Network）等によつて互いに接続されていても良い。
【００５７】
（３−２）分離型システム
次に分離型システムの例として、ＡＶ信号（オーデイオ信号及びビデオ信号）を記録媒体の物理的な配送を介して多数の端末装置に分配するＡＶサーバシステムについて説明する。図７にＡＶサーバシステム２１の全体構成を示す。
このＡＶサーバシステム２１はそれぞれ地理的に離れた位置にある制作局２２、キー局２３、人工衛星２４、ケーブル局２５、支局２６、家庭２７等によつて構成されるシステムである。
【００５８】
この例の場合、基本システムにて説明した記録装置１は制作局２２のエンコーダ２２Ａに相当し、再生装置２は支局２６のデコーダ２６Ａに相当する。
制作局２２は映像ソースを編集してコマーシヤル（ＣＭ）やプログラム（番組）を制作する制作会社や制作室であり、番組やＣＭの動画像がここで圧縮符号化され記録媒体３に記録されるようになされている。記録媒体３はキー局２３やケーブル局２５に物理的に配送される。
【００５９】
キー局２３は記録媒体３から再生した画像データを圧縮符号化データのまま人工衛星２４に送出し、これを遠隔地の支局２６に伝送する際に使用される。このデータ伝送は基本システムにおける記録媒体３と再生装置２間が無線伝送になつたものである。
一方、ケーブル局２５は記録媒体３から再生した画像データを圧縮符号化データのままケーブルを介して遠隔地の支局２６に伝送する際に使用される。この他、ケーブル局２５と支局２６との間のデータ伝達には記録媒体３によるものもある。
【００６０】
支局２６にはデコーダ２６Ａ及びフアイルサーバ２６Ｂが設けられており、受信された符号化データを元のデータレートで復号し、動画像信号として各家庭２７に配信するのに使用される。
基本システムはこのような応用も可能である。またこの例ではエンコーダ２２が制作局２２に設けられている例を表したが、キー局２３内にあつても良い。
またデコーダ２６Ａを支局２６内に設ける例について表したが、各家庭２７内に設けられている例についても実現できる。
【００６１】
（４）他の実施例
なお上述の実施例においては、記録装置１としてエンコーダ１Ａとパケツト化処理部１Ｂ、ＦＩＦＯバツフアメモリ１Ｃ及びパデイングパケツト処理部１Ｄが一体化されているものについて述べたが、本発明はこれに限らず、それぞれ別筺体内に内蔵されていても良い。
同様に再生装置２としてデータ抽出処理部２Ａ、ＦＩＦＯバツフアメモリ２Ｂ及びデコーダ２Ｃが一体化されているものについて述べたが、本発明はこれに限らず、それぞれ別筺体内に内蔵されていても良い。
【００６２】
さらに上述の実施例においては、記録媒体３の例としてハードデイスクやビデオテープを用いる場合について述べたが、本発明はこれに限らず、他の記録媒体にも適用し得る。例えばビデオデイスクや光磁気デイスク、また相変化型デイスクのような光デイスクやいわゆる光カードにも適用し得る。またフロツピーデイスク等の磁気記録媒体にも適用し得る。
【００６３】
さらに上述の実施例においては、記録媒体３からデータを読み出すとき、記録媒体に書き込むときと同じレートＲｗで読み出す場合について述べたが、読み出し時のレートはこれ以上であつても良い。
【００６４】
【発明の効果】
上述のように本発明によれば、通常、動画像信号を圧縮符号化する場合、発生データ量が変動するが、これら変動に係わらず記録媒体に記録される時点又は伝送路に出力される時点における圧縮符号化データは一定サイズのパケツトデータに変換されており、発生データ量の多寡によらず一定時間内に動画像信号の記録又は伝送を完了できる。これにより再生時又は受信時において、発生データ量の多寡によらず常に一定時間内に動画像信号を再生又は受信でき、伸張復号化した動画像信号の連続再生が可能となる。
【図面の簡単な説明】
【図１】本発明によるデータ記録装置及びデータ再生装置の基本構成を示すブロツク図である。
【図２】データ記録装置による記録動作を示すフローチヤートである。
【図３】データ再生装置による再生動作を示すフローチヤートである。
【図４】記録時におけるデータ発生量と処理時間の関係を示す略線図である。
【図５】再生時におけるデータ発生量と処理時間の関係を示す略線図である。
【図６】ＡＶサーバシステムの構成例を示すブロツク図である。
【図７】ＡＶサーバシステムの構成例を示すブロツク図である。
【符号の説明】
１……記録装置、１Ａ……エンコーダ、１Ａ１……圧縮符号化処理部、１Ａ２……エンコードバツフアメモリ、１Ｂ……パケツト化処理部、１Ｃ……ＦＩＦＯバツフアメモリ、１Ｄ……パデイングパケツト処理部、２……再生装置、２Ａ……データ抽出処理部、２Ｂ……ＦＩＦＯバツフアメモリ、２Ｃ……デコーダ、２Ｃ１……デコードバツフアメモリ、２Ｃ２……伸張復号化処理部、１１、２１……ＡＶサーバシステム、１２……データ供給源、１３……エンコーダ部、１４……サーバ部、１４Ａ……記録再生部、１４Ｂ……デコーダ部、１５Ａ１〜１５ＡＮ……端末、２２……制作局、２３……キー局、２４……人工衛星、２５……ケーブル局、２６……支局、２７……家庭。[0001]
【table of contents】
The present invention will be described in the following order.
Industrial Field of Application Means for Solving the Problems to be Solved by the Conventional Invention (1) Principle of Recording Method and Reproducing Method (2) Basic System Configuration (2-1) Recording Device and Reproduction Configuration of apparatus (2-2) Recording procedure and reproduction procedure (3) Application system (3-1) Integrated system (3-2) Separable system (4) Effects of other embodiments of the invention
[Industrial application fields]
The present invention relates to a data recording apparatus, a data reproducing apparatus, and the like for recording and reproducing a moving image signal by compression encoding.
The present invention also relates to a data transmission apparatus that compresses and encodes a moving image signal and transmits it to a remote location.
[0003]
[Prior art]
In general, in a system for recording / reproducing a digital moving image signal or a system for transmitting it to a remote place, a method of compressing and encoding the image signal is employed in order to efficiently use the capacity and transmission path of the recording medium. At this time, it is common to compress and encode a moving image signal using intra-frame correlation or inter-frame correlation. Incidentally, these compression coding formats include MPEG1, MPEG2 and H.264. 261 etc.
Now, in a compression encoding device or the like that operates based on these encoding formats, encoding is performed so that the data amount of a moving image signal generated within a certain time is constant.
[0004]
[Problems to be solved by the invention]
However, the amount of data generated by compression encoding is not usually constant, and the amount of data generated for each frame differs.
However, if the amount of data generated per time is not constant, it is extremely difficult to directly record or transmit the generated data to a recording medium.
This is because the data recording rate or data transmission rate is generally constant.
[0005]
Therefore, normally, a buffer memory is installed between the moving image compression coding processing unit and the medium recording unit or between the moving image compression coding processing unit and the transmission unit, and the variable amount output to the recording device, the transmission path, or the like. The data rate of the encoded data is made constant. At this time, the moving image compression encoding processing unit adjusts the generation amount of the encoded data so that the buffer memory is not broken.
[0006]
Therefore, the average rate of the data amount generated per unit time in the moving image compression coding processing unit during moving image compression coding is the same as the data rate of the coded data output from the buffer memory.
In general, a device that performs these operations is called an encoder including a buffer memory.
[0007]
On the other hand, on the device side that decodes the compression-coded data into the original moving image signal, a buffer memory similar to that described above is placed between the recording device or the output end of the transmission path and the decompression decoding processing unit. Has been made. In general, an apparatus that performs these operations is called a decoder including a buffer memory.
As described above, in the conventional encoder or decoder, the compression encoding process is performed so that the data amount of the moving image signal approaches a certain amount in a certain time unit, or approaches the target encoded data generation amount, depending on the application. Yes.
[0008]
Here, encoded data obtained by compressing and encoding a moving image signal of time length T is recorded on a recording medium at a writing rate R, and then the recorded data is read and decoded at a reading rate R to reproduce the moving image signal. Think about the case. In this case, the target encoded data generation amount Ei is expressed by the following equation:

It becomes.
[0009]
However, the actual data generation amount Er is expressed by the following equation:

As shown in FIG. 4, the constant value R × T is not reached. Here, B is the capacity of the buffer memory provided in the encoder.
[0010]
Considering the case where this data is recorded on the recording medium as it is and then read out, the reading time t is given by the following equation:

It becomes. The read data is decoded into a moving image signal by the decoder, but the reproduction time of the decoded moving image signal is still T. From this, it can be seen that the image reproduction time and the data read time required for the image are different.
[0011]
By the way, as in an AV server, data obtained by compressing and encoding a moving image signal for a certain time (hereinafter referred to as a clip) is written to an arbitrary number of media, and an arbitrary number of clips are read from the media. When image signals are continuously reproduced, there are the following problems.
[0012]
If you write an arbitrary number of clips, which are compression-coded moving image signals for a certain time, onto a medium, and continuously play an arbitrary number of clip image signals from that medium, the time to read out the necessary data will be different, When the data read time is longer than the reproduction time, there is a problem that the actual clip image signal cannot be reproduced continuously without interruption.
[0013]
The present invention has been made in consideration of the above points, and a data recording method and apparatus, a data reproducing method and apparatus, a recording medium, a data transmission method, and a data recording method capable of reproducing a clip image having an arbitrary length of time without interruption. The device is to be proposed.
[0014]
[Means for Solving the Problems]
In order to solve such a problem, in the present invention, when packet data obtained by compressing and encoding a moving image signal for a certain time after being compressed and encoded is recorded on a recording medium or output to a transmission line, a certain time from the start of packet data output. During this period, the packet data is simply written in the first-in first-out buffer memory, and reading to the recording medium or transmission path is prohibited.
Eventually, after a certain period of time has elapsed since the start of packet data output, the packet data after compression encoding is written to the first-in first-out buffer memory, while the packet data written to the first-in first-out buffer memory is at a data rate higher than that at the time of writing. The data is read and recorded on a recording medium or output to a transmission path.
[0015]
On the other hand, packet data from a recording medium in which compressed encoded data formed by compressing and encoding a moving image signal for a certain period of time is always converted into packet data of a fixed size regardless of the amount of data generated by the compressed encoded data. When reading or receiving from the transmission path, the packet data is read at a data rate when writing to the recording medium or a data rate equal to or higher than the data rate when outputting to the transmission path, and written to the first-in first-out buffer memory. . After that, the packet data already written in the first-in first-out buffer memory is read out and decoded at almost the same data rate as when packetized.
[0016]
[Action]
Normally, when a moving image signal is compression-encoded, the amount of generated data fluctuates. Regardless of these fluctuations, the compression-encoded data at the time of recording on a recording medium or the time of output to a transmission line is packet data of a certain size Is converted to Therefore, recording or transmission of a moving image signal can be completed within a certain time regardless of the amount of generated data.
On the other hand, the reproduction side or the reception side can reproduce or receive the compressed encoded data of the moving image signal within a predetermined time regardless of the amount of generated data.
[0017]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0018]
(1) Principle of recording method and reproducing method Data obtained by compressing and coding a moving image for a certain period of time, that is, writing an arbitrary number of clips on a recording medium, and an arbitrary number of image signals from the recording medium continuously. In order to reproduce data, the recording apparatus shown in this embodiment writes the packetized data after compression encoding into the FIFO buffer memory for a certain period of time, and then reads out the data at a data rate higher than that at the time of writing and records it on the recording medium. To do.
[0019]
Further, the reproducing apparatus shown in this embodiment extracts data from a packet read from the recording medium at the same rate or higher than that at the time of recording, and writes this data into a FIFO buffer memory having a capacity larger than that at the time of recording. It reads out at the same rate as the time of encoding and performs decompression decoding processing.
[0020]
(2) Basic System Configuration (2-1) Configuration of Recording Device and Reproducing Device FIG. 1 shows a hardware configuration example of a recording device 1 that realizes these recording methods and a reproducing device 2 that realizes these reading methods.
First, the configuration of the recording apparatus 1 will be described. The recording apparatus 1 includes an encoder 1A, a packetization processing unit 1B, a FIFO buffer memory 1C, and a padding packet processing unit 1D.
[0021]
The encoder 1A includes two components, a compression encoding processing unit 1A1 and an encode buffer memory 1A2. The compression encoding processing unit 1A1 compresses and encodes the moving image signal S1 at an average rate Re by a variable amount, and sequentially outputs the encoded data S2 to the encoding buffer memory 1A2 having the capacity Be.
The encode buffer memory 1A2 outputs the encoded data S2 at the rate Re when the encoded data S2 is stored in the memory in a certain amount. Incidentally, the remaining buffer amount Be in the encode buffer memory 1A2 is fed back to the compression encoding processing unit 1A1, so that the buffer does not fail.
[0022]
The packet processing unit 1B sequentially receives the encoded data S3 output from the encoder 1A, stores them in one or a plurality of packets, and outputs them. At this time, the packet processing unit 1B writes necessary information such as the packet size, data type, and time information in the packet header, and outputs the information to the FIFO buffer memory 1C at the same constant rate Re as that at the time of encoding.
[0023]
The FIFO buffer memory 1C is a buffer memory having a capacity Bw provided for data rate conversion. The FIFO buffer memory 1C accumulates the packet data S4 written at the rate Re for a predetermined time Tw, and then reads it at a read rate Rw higher than the rate Re at the time of writing and records it on the recording medium 3.
[0024]
As a result, the packet data S5 can be written to the recording medium 3 within the time corresponding to the clip time T regardless of the amount of information generated during encoding.
Incidentally, the accumulation time Tw, read rate Rw, and buffer capacity Bw of the FIFO buffer memory 1C during this read operation are calculated as follows.
[Expression 4]

[Equation 5]

[Formula 6]

[0025]
Incidentally, there is a possibility that the FIFO buffer memory 1C may lose internal data while writing data to the recording medium 3 because of the relationship Rw> Re. A padding packet processing unit 1D is provided in preparation for this situation.
The padding packet processing unit 1D constantly detects the buffer remaining amount Be in the FIFO buffer memory 1C, and when the buffer remaining amount Be becomes 0, it means a meaningless packet (that is, padding packet not directly related to data). ) Is output to fill the blank period. This prevents the transmission form from failing.
[0026]
Next, the configuration of the playback device 2 will be described. The playback device 2 is composed of a data extraction processing unit 2A, a FIFO buffer memory 2B, and a decoder 2C.
The reproducing device 2 reads the recording data recorded on the recording medium 3 at a constant rate Rw, and reads this as reproducing data S6 into the data extraction processing unit 2A.
The data extraction processing unit 2A removes and discards the padding packet from the reproduction data S6 to be read, and extracts only the encoded data S7 corresponding to the moving image signal and sends it to the read FIFO buffer memory 2B. Has been made.
[0027]
At this time, if the read rate when the data extraction processing unit 2A reads the record data S6 from the recording medium 3 is Rw which is the same as the write rate, the time Td required for the read is expressed by the following equation:

Thus, it can be seen that the clip can always be kept within the display time of the clip.
[0028]
Thus, the encoded data S7 extracted by the data extraction processing unit 2A is written into the read-out FIFO buffer memory 2B, and the data rate is returned to the original data rate. The capacity Br of the read FIFO buffer memory 2B satisfies the following condition.
[0029]
In general, the capacity of the decode buffer memory 2C1 built in the decoder 2C is greater than the capacity of the encode buffer memory 1A2. Therefore, in this embodiment, the capacity Br of the FIFO buffer memory 2B for reading is as follows. Formula [8]

As shown in FIG. 4, a memory having a capacity equal to or larger than the capacity Bw of the FIFO buffer memory 1B for writing is used.
[0030]
Finally, the decoder 2C will be described. The decoder 2C is composed of a decode buffer memory 2C1 and a decompression decoding processing unit 2C2.
The decode buffer memory 2C1 reads the encoded data S8 from the FIFO buffer memory 2B at a constant rate Re and supplies it to the decompression decoding processor 2C2. The decompression decoding unit 2C2 decodes the encoded data S8 at the average decoding rate Re, and outputs the decoding result as a moving image signal S10.
[0031]
(2-2) Recording Procedure and Reproducing Procedure In the above configuration, the recording operation and the reproducing operation executed in the recording apparatus 1 and the reproducing apparatus 2 at the time of recording and at the time of reproduction will be described in order.
First, a recording operation during recording assuming that a plurality of clips can be continuously reproduced without interruption will be described with reference to FIG.
[0032]
When the recording operation is started, the recording apparatus 1 moves from step SP1 to step SP2, and designates the position on the recording medium 3 where the moving image signal is recorded by the writing pointer. This pointer is used as a read pointer for reading the recording data of the moving image signal during reproduction.
When the designation of the write pointer is completed, the processing of the recording apparatus 1 moves to step SP3, the moving image signal S1 is input to the encoder 1A, and variable amount encoding is started.
[0033]
When encoding is started, the recording apparatus 1 encodes the moving image signal S1 at the average rate Re by the encoder 1A, and the encoded data S3 obtained by the encoding as shown in step SP4. Are sequentially packetized. At the same time, the recording apparatus 1 starts to write packetized packet data S4 into the FIFO buffer memory 1C.
As shown in the next step SP5, the recording apparatus 1 confirms the elapsed time from the writing start time and determines whether or not the elapsed time is longer than the accumulation time Tw given by equation (4).
[0034]
If a positive result is eventually obtained, the recording apparatus 1 starts reading the packet data S5 from the FIFO buffer memory 1B as shown in step SP6. As described in the previous section, the data rate Rw at the time of reading is a data rate larger than the data rate Re when writing to the FIFO buffer memory 1C.
[0035]
Thereafter, as shown in step SP7, the recording apparatus 1 returns from step SP7 to step SP6 until it is confirmed that the buffer remaining amount Be in the FIFO buffer memory 1C becomes 0, and the packet data S5 read from the FIFO buffer memory 1C is returned. To the recording medium 3 is continued.
If a positive result is obtained in step SP7 and it is confirmed that the FIFO buffer memory 1C is empty, the recording apparatus 1 determines whether or not all the writing of the packet data S4 to the FIFO buffer memory 1B is completed in step SP8. Move on to the determination process.
[0036]
If a negative result is obtained at this time, the recording apparatus 1 determines that the FIFO buffer memory 1C is temporarily emptied because the read rate Rw is larger than the write rate Re, and the process moves to step SP8, where there is a lack of packets. Fill the minutes with padding packets.
Thereafter, the recording apparatus 1 returns to step SP7 to determine again whether the remaining buffer amount Be is 0. If it is not 0, writing to the recording medium 3 is resumed. If it is 0, the recording apparatus 1 again returns to step SP8. It is determined whether or not writing to the FIFO buffer memory 1C has been completed.
[0037]
When an affirmative result is finally obtained at step SP8, the end of recording of the series of moving image signals S1 is confirmed at step SP10, and the process proceeds to the determination of whether or not to record the moving image signal S1 of the next clip at the next step SP11. .
While a positive result is obtained here, the recording apparatus 1 repeatedly executes the processing of step SP2 to step SP11. When a negative result is obtained, recording of a plurality of clips is terminated.
[0038]
Next, the reproducing operation when reproducing the recording data from the recording medium 3 recorded in this way will be described with reference to FIG.
When the reproducing apparatus 2 starts the reproducing operation, the process proceeds from step SP21 to step SP22, and the position on the recording medium 3 from which the recording data is read is designated by the reading pointer.
When the designation of the read pointer is completed, reading from the recording medium 3 is started as shown in step SP23.
[0039]
When the reproduction device 2 reads the reproduction data S6 into the data extraction processing unit 2A, as shown in step SP24, the reproduction apparatus 2 extracts data unrelated to the encoded data, such as padding packets, from the reproduction data S6 read at the constant rate Rw. Remove.
Thereafter, the playback device 2 supplies the encoded data S7 of the moving image signal portion to the FIFO buffer memory 2B at step SP25.
In the following step SP26, the reproducing apparatus 2 gives the encoded data S8 rate-converted by the FIFO buffer memory 2B to the decoder 2C, and starts reproducing the moving image signal S10 by the decoder 2C.
[0040]
Then, in the next step SP28, the reproducing apparatus 2 determines whether or not all the data reading has been completed, and while a negative result is obtained, step SP29-step SP24-step SP25-step SP26-step SP27-step SP28. Repeat the process.
When the data reading for one clip is completed by repeating this processing loop, the reproducing apparatus 2 moves from step SP28 to step SP29, and proceeds to a determination process as to whether there is a next clip to be continuously reproduced.
[0041]
While the affirmative result is obtained here, the reproducing apparatus 2 repeats the processing of step SP22 to step SP28, and proceeds to the processing of step SP30 when a negative result is obtained.
Then, at step SP30, when it is confirmed that the buffer remaining amount of the decode buffer memory 2C1 has become 0, the process proceeds to step SP31 and the reproduction operation is terminated.
[0042]
FIG. 4 and FIG. 5 show the relationship between the amount of data and the processing time when two clips 1 and 2 are continuously recorded as an example of the above recording / reproducing operation.
First, assume that the image times of clip 1 and clip 2 recorded continuously are T and T ′, respectively, as shown in FIG. In general, since image data encoded immediately before remains in the encode buffer memory 1A2 of the encoder 1A, the encoded data S3 of the clip 1 and clip 2 is read from the FIFO buffer memory 1B as shown in FIG. Thus, it takes time of T + ΔT and T ′ + ΔT ′.
[0043]
If this encoded data S3 is recorded on the recording medium 3 as it is in the conventional manner, the time of T + ΔT and T ′ + ΔT ′ is also required to reproduce the clip 1 and the clip 2 from the recording medium 3, It will be long. For this reason, even if two clips 1 and 2 are continuously reproduced in the conventional reproducing apparatus, there is a possibility that a blank time of ΔT is generated at the time of display.
[0044]
On the other hand, the recording apparatus 1 shown in the present embodiment reads the data from the FIFO buffer memory 1B at a data rate higher than the average encoding rate Re and satisfies the expression (5). Writing to the recording medium 3 can be completed within the image times T and T ′ regardless of the amount of the buffer remaining amount Be. This is shown in FIG. Incidentally, the time indicated by diagonal lines in the figure is a period during which padding packets are filled.
At the end of recording, data is recorded on the recording medium 3 with the data structure shown in FIG.
[0045]
On the other hand, at the time of reproduction, the reproducing apparatus 2 can read the recording data of the moving image signal corresponding to the clip 1 and the clip 2 within the times T and T ′, respectively, as shown in FIG.
In addition, since data irrelevant to the encoded data, such as padding packets, is extracted from the read reproduction data S6, the data read to the FIFO buffer memory 2B is truly converted into a moving image signal as shown in FIG. Only the corresponding data.
[0046]
Thereafter, the encoded data S8 is read from the FIFO buffer memory 2B to the decoder 2C at the original data rate Re and decoded as shown in FIG. 5C. At this time, in FIG. 5C, the buffer remaining amount and the apparent data read time are longer than the display time of the clip 1 and the clip 2, but the decoding operation of each encoded data is performed at the times T and T ′. Since the processing ends, two clips 1 and 2 can be continuously reproduced as shown in FIG.
[0047]
According to the above configuration, the moving image signals of two clips to be continuously reproduced can be read from the recording medium 3 within each display time T and T ′, thereby avoiding a clip display delay due to a delay in decoding operation. it can. As a result, a recording apparatus 1 and a reproducing apparatus 2 that can continuously reproduce a plurality of clips without a blank period can be realized. Further, a recording medium 3 capable of continuous reproduction can be realized.
[0048]
(3) Application system An example of a system configuration in which this basic system is applied is shown below. Here, there is an integrated system in which the recording device 1, the recording medium 3 and the reproducing device 2 are respectively connected by communication lines, and between the recording device 1 and the recording medium 3 or between the recording medium 3 and the reproducing device 2. A separate system that is not connected by a wired path will be described.
[0049]
(3-1) Integrated System Here, as an example of the integrated system, a server system (hereinafter referred to as an AV server system) that distributes AV signals (audio signals and video signals) to a large number of terminal devices via a communication line will be described. To do. FIG. 6 shows the overall configuration of the AV server system 11.
This AV server system 11 is composed of three parts: a data supply source 12, an encoding unit 13, and a server unit 14, and is used to distribute AV signals from the server unit 14 to a large number of terminals 15A1 to 15AN. . Each part is configured as follows.
[0050]
The data supply source 12 includes a playback device 12A such as a video tape recorder (VTR) or a magneto-optical disk device. Each reproduction device 12A supplies AV data signals SD1, SD2,... To the encoding unit 13 through a transmission path or a signal line. In this example, a plurality of data supply sources 12 are provided.
The encoding unit 13 is a part corresponding to the recording apparatus 1 of the basic system, and includes an encoder 13A, a FIFO buffer / packet processing unit 13B, and a control unit 13C.
[0051]
Of these, the encoder 13A encodes the AV data signals SD1, SD2,... Input from the respective data supply sources 12 into data format signals according to the MPEG2 standard, and converts them into data streams D1, D2,. ing.
The FIFO buffer / packet processing unit 13B temporarily stores these data streams D1, D2,... In the FIFO buffer memory, converts the rates, and converts the rate-converted encoded data into packet data by the packet processing unit.
[0052]
Control unit 13C is Yotsute data source 12 to the control signal S _CTL, it has been made to manage each part of the operating state and controls the encoder 13A and the server unit 14.
[0053]
The server 14 includes a recording / reproducing unit 14A and a decoding unit 14B. Here, the recording / reproducing unit 14A records the encoded data obtained by further compressing the encoded data in the time axis direction on the recording medium, and reads the corresponding AV data when instructed by the user. It is used to output to the decoding unit 14B. Incidentally, an instruction from the user is input as a request signal S _request .
[0054]
The recording / reproducing unit 14A includes a media control unit 14A1 and a plurality of media units 14A2 to 14A8. Here, the media control unit 14A1 is a unit for controlling the recording / reproducing operations of the plurality of media units 14A2 to 14A8. Each of the media units 14A2 to 14A8 incorporates a plurality of hard disk devices so that a plurality of signals can be simultaneously recorded and reproduced. Thereby, multi-access from many terminals 15A1 to 15AN can be realized. In addition, a clip moving image signal for which continuous reproduction is required is recorded on these hard disks.
[0055]
The decoding unit 14B includes a data extraction processing unit / FIFO buffer memory 14B0 and a plurality of decoders 14B1 to 14BM. Here, the number of decoders 14B1 to 14BM prepared in the decoding unit 14B is determined according to the number of terminals 15A1 to 15AN to be finally connected and the number of encoded data that can be simultaneously reproduced by the recording / reproducing unit 14A.
[0056]
The decoding unit 14B decodes the encoded data read by the decoders 14B1 to 14BM via the media units 14A2 to 14A8 and outputs the decoded data to the terminals 15A1 to 15AN.
The AV server system 11 is not necessarily provided in one room, and may be connected to each other by a LAN (Local Area Network) or the like.
[0057]
(3-2) Separation Type System Next, as an example of the separation type system, an AV server system that distributes AV signals (audio signals and video signals) to a large number of terminal devices via physical delivery of recording media will be described. . FIG. 7 shows the overall configuration of the AV server system 21.
This AV server system 21 is a system constituted by a production station 22, a key station 23, an artificial satellite 24, a cable station 25, a branch office 26, a home 27, etc., which are geographically separated from each other.
[0058]
In this example, the recording apparatus 1 described in the basic system corresponds to the encoder 22A of the production station 22, and the playback apparatus 2 corresponds to the decoder 26A of the branch station 26.
The production station 22 is a production company or production room that edits a video source to produce a commercial (CM) or a program (program), and a moving image of the program or CM is compressed and encoded here and recorded on the recording medium 3. It is made like that. The recording medium 3 is physically delivered to the key station 23 and the cable station 25.
[0059]
The key station 23 is used when the image data reproduced from the recording medium 3 is sent to the artificial satellite 24 as compressed and encoded data and is transmitted to the branch office 26 at a remote location. This data transmission is a wireless transmission between the recording medium 3 and the playback device 2 in the basic system.
On the other hand, the cable station 25 is used when transmitting the image data reproduced from the recording medium 3 to the branch office 26 at a remote location via the cable as the compressed encoded data. In addition, some data transmission between the cable station 25 and the branch office 26 is performed by the recording medium 3.
[0060]
The branch office 26 is provided with a decoder 26A and a file server 26B, which are used to decode the received encoded data at the original data rate and distribute it as a moving picture signal to each home 27.
The basic system can be applied in this way. In this example, the encoder 22 is provided in the production station 22. However, the encoder 22 may be provided in the key station 23.
Further, the example in which the decoder 26A is provided in the branch office 26 has been described, but the example provided in each home 27 can also be realized.
[0061]
(4) Other Embodiments In the above-described embodiment, the recording apparatus 1 is described in which the encoder 1A, the packetization processing unit 1B, the FIFO buffer memory 1C, and the padding packet processing unit 1D are integrated. The present invention is not limited to this, and each may be built in a separate enclosure.
Similarly, the data extraction processing unit 2A, the FIFO buffer memory 2B, and the decoder 2C that are integrated as the playback device 2 have been described. However, the present invention is not limited to this, and each may be built in a separate housing.
[0062]
Furthermore, in the above-described embodiment, the case where a hard disk or a video tape is used as an example of the recording medium 3 has been described. However, the present invention is not limited to this and can be applied to other recording media. For example, the present invention can also be applied to an optical disk such as a video disk, a magneto-optical disk, a phase change disk, or a so-called optical card. The present invention can also be applied to a magnetic recording medium such as a floppy disk.
[0063]
Further, in the above-described embodiment, the case where data is read from the recording medium 3 is read at the same rate Rw as that written to the recording medium, but the reading rate may be higher.
[0064]
【The invention's effect】
As described above, according to the present invention, when a moving image signal is normally compressed and encoded, the amount of generated data fluctuates. The compressed and encoded data is converted into packet data of a certain size, and recording or transmission of a moving image signal can be completed within a certain time regardless of the amount of generated data. Thus, at the time of reproduction or reception, the moving image signal can always be reproduced or received within a predetermined time regardless of the amount of generated data, and continuous reproduction of the expanded and decoded moving image signal becomes possible.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of a data recording apparatus and a data reproducing apparatus according to the present invention.
FIG. 2 is a flowchart showing a recording operation by the data recording apparatus.
FIG. 3 is a flowchart showing a reproducing operation by the data reproducing apparatus.
FIG. 4 is a schematic diagram showing a relationship between a data generation amount and processing time during recording.
FIG. 5 is a schematic diagram showing the relationship between the amount of data generated during playback and the processing time.
FIG. 6 is a block diagram illustrating a configuration example of an AV server system.
FIG. 7 is a block diagram showing a configuration example of an AV server system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Recording device, 1A ... Encoder, 1A1 ... Compression encoding processing unit, 1A2 ... Encoding buffer memory, 1B ... Packetization processing unit, 1C ... FIFO buffer memory, 1D ... Padding packet processing 2, 2 ... playback device, 2A ... data extraction processing unit, 2B ... FIFO buffer memory, 2C ... decoder, 2C1 ... decode buffer memory, 2C2 ... decompression decoding processing unit, 11, 21 ... AV Server system, 12 ... Data supply source, 13 ... Encoder unit, 14 ... Server unit, 14A ... Recording / playback unit, 14B ... Decoder unit, 15A1-15AN ... Terminal, 22 ... Production station, 23 ... ... key station, 24 ... artificial satellite, 25 ... cable station, 26 ... branch office, 27 ... home.

Claims (12)

Shall apply in the data recording method for recording a plurality of packet data generated by a certain time period the compression encoding and packet processing on the moving image signal is sequentially applied to the recording medium,
From the data writing starts a predetermined setting period, a first step of sequentially writing the packet data to the buffer memory,
After the lapse of the setting period forward, writes sequentially the remaining of the packet data to the upper Symbol buffer memory, the packet data written in the buffer memory, the written order, onto type recording medium at data rates when writing With the second step
With
The above setting period is
That it has been set from the top Ki圧 condensation coding processing performed encoding process encoding provided in unit buffer memory than the time which is the minimum required to read the data corresponding to the total volume of the coding buffer memory A characteristic data recording method. Shall apply in the data recording method for recording a plurality of packet data generated by a certain time period the compression encoding and packet processing on the moving image signal is sequentially applied to the recording medium,
From the data writing starts a predetermined setting period, a first step of sequentially writing the packet data to the buffer memory,
After the lapse of the setting period forward, writes sequentially the remaining of the packet data to the upper Symbol buffer memory, the packet data written in the buffer memory, the written order, onto type recording medium at data rates when writing With the second step
With
Above Kide Tareto is,
A compression coded data compression coding processing for the moving image signal of the predetermined time period is obtained as a result of decorated, all of the coding buffer memory provided an equivalent piezoelectric reduced coding processing facilities to encoding processing unit A data recording method, characterized in that the data rate is such that data corresponding to a capacity can be transferred to the recording medium within the set period . An encoding unit for performing compression coding processing on the moving image signal of a certain time period,
A packet processing section for performing packet processing on encoded data generated by the compression encoding process,
Between the data writing start of a predetermined setting period, sequentially writing the plurality of packet data generated by said packet processing, after elapse of the set period, the successively writes the remainder of the packet data, the written It was packet data, the written order, comprising a buffer memory for forwarding to the record medium at data rates during writing,
For a certain period of time,
A data recording apparatus characterized in that it is set to a time required for reading out data corresponding to the entire capacity of the encoding buffer memory from the encoding buffer memory provided in the encoding processing unit. An encoding unit for performing compression coding processing on the moving image signal of a certain time period,
A packet processing section for performing packet processing on encoded data generated by the compression encoding process,
Between the data writing start of a predetermined setting period, sequentially writes the multiple packet data generated by said packet processing, after elapse of the set period, the successively writes the remainder of the packet data, the written the packet data that is, the written order, comprising a buffer memory for forwarding to the record medium at data rates during writing,
Above Kide Tareto is,
And the encoded data, and wherein the the data corresponding to the total volume of the coding buffer memory provided in the encoding unit is a data rate that can be transferred to the recording medium within the set period Data recording device. A certain time of the plurality of packet data to compression encoding processing and the packet processing is obtained as a result of successively applied on the moving image signal is sequentially written into the first buffer memory, after a predetermined set time period, the written the sequentially, shall apply in the data reproducing method for reproducing the packet data recorded on the outlet to a recording medium to read from said first buffer memory at data rates during writing,
A first step of reading the packet data recorded on the recording medium at a data rate equal to or higher than the data rate at the time of recording ;
A second step of reading out the packet data read out at a data rate equal to or higher than the data rate at the time of recording and written into the second buffer memory at the same data rate as when written into the first buffer memory;
With
The above setting period is
The time is set to be more than the minimum time required to read out data corresponding to the entire capacity of the coding buffer memory from the coding buffer memory provided in the coding processing unit that performs the compression coding processing. A data reproduction method characterized by the above. A certain time of the moving image signal a plurality of packet processing is obtained as a result of performed on encoded data obtained by compression coding the packet data are sequentially written into the first buffer memory, lapse of a predetermined setting period later, the written order, reads the packet data recorded on the read out by the recording medium at data rates when writing from the first buffer memory, the data extraction unit for extracting the encoded data from the packet data When,
For writing the packet data recorded on the recording medium at a data rate equal to or higher than the data rate at the time of recording, and for reading the written packet data at the same data rate as when written to the first buffer memory. With a second buffer memory
With
The above setting period is
The time is set to be more than the minimum time required to read out data corresponding to the entire capacity of the coding buffer memory from the coding buffer memory provided in the coding processing unit that performs the compression coding processing. A data reproducing apparatus characterized by that. Shall apply in the data transmission method for outputting a plurality of packet data generated by a certain time period the compression encoding and packet processing on the moving image signal is sequentially applied to the transmission line,
From the data writing starts a predetermined setting period, a first step of sequentially writing the packet data to the buffer memory,
After the lapse of the setting period output, writes sequentially the remaining of the packet data to the upper Symbol buffer memory, the packet data written in the buffer memory, the written order on Symbol transmission line at data rates when writing With the second step
With
The above setting period is
That it has been set from the top Ki圧 condensation coding processing performed encoding process encoding provided in unit buffer memory than the time which is the minimum required to read the data corresponding to the total volume of the coding buffer memory Characteristic data transmission method. Shall apply in the data transmission method for outputting a plurality of packet data generated by a certain time period the compression encoding and packet processing on the moving image signal is sequentially applied to the transmission line,
From the data writing starts a predetermined setting period, a first step of sequentially writing the packet data to the buffer memory,
After the lapse of the setting period output, writes sequentially the remaining of the packet data to the upper Symbol buffer memory, the packet data written in the buffer memory, the written order on Symbol transmission line at data rates when writing With the second step
With
Above Kide Tareto is,
A compression coded data compression coding processing for the moving image signal of the predetermined time period is obtained as a result of decorated, all of the coding buffer memory provided an equivalent piezoelectric reduced coding processing facilities to encoding processing unit A data transmission method characterized by a data rate at which data corresponding to a capacity can be output to the transmission line within the set period . An encoding unit for performing compression coding processing on the moving image signal of a certain time period,
A packet processing section for performing packet processing on encoded data generated by the compression encoding process,
Between the data writing start of a predetermined setting period, sequentially writing the plurality of packet data generated by said packet processing, after elapse of the set period, the successively writes the remainder of the packet data, the written It was packet data, the written order, comprising a buffer memory for outputting the transfer feed path at data rates during writing,
For a certain period of time,
A data transmission apparatus, wherein the time is set to be longer than a minimum time required to read out data corresponding to the entire capacity of the encoding buffer memory from the encoding buffer memory provided in the encoding processing unit. An encoding unit for performing compression coding processing on the moving image signal of a certain time period,
A packet processing section for performing packet processing on encoded data generated by the compression encoding process,
Between the data writing start of a predetermined setting period, sequentially writing the plurality of packet data generated by said packet processing, after elapse of the set period, the successively writes the remainder of the packet data, the written It was packet data, the written order, comprising a buffer memory for outputting the transfer feed path at data rates during writing,
Above Kide Tareto is,
And the encoded data, and wherein the the data corresponding to the total volume of the coding buffer memory provided in the encoding unit is a data rate that can be outputted to the transmission line within the set period Data transmission equipment. A certain time of the plurality of packet data to compression encoding processing and the packet processing is obtained as a result of successively applied on the moving image signal is sequentially written into the first buffer memory, after a predetermined set time period, the written the sequentially, shall apply in the data transmission method for transmitting the packet data recorded on the recording medium at data rates when writing is read out from said first buffer memory,
A first step of reading the packet data recorded on the recording medium at a data rate equal to or higher than the data rate at the time of recording ;
A second step of reading out the packet data read out at a data rate equal to or higher than the data rate at the time of recording and written into the second buffer memory at the same data rate as when written into the first buffer memory;
With
The above setting period is
The time is set to be more than the minimum time required to read out data corresponding to the entire capacity of the coding buffer memory from the coding buffer memory provided in the coding processing unit that performs the compression coding processing. A data transmission method characterized by the above. A certain time of the moving image signal a plurality of packet processing is obtained as a result of performed on encoded data obtained by compression coding the packet data are sequentially written into the first buffer memory, lapse of a predetermined setting period later, the written order, reads the packet data recorded on the read out by the recording medium at data rates when writing from the first buffer memory, the data extraction unit for extracting the encoded data from the packet data When,
For writing the packet data recorded on the recording medium at a data rate equal to or higher than the data rate at the time of recording, and for reading the written packet data at the same data rate as when written to the first buffer memory. With a second buffer memory
With
The above setting period is
The time is set to be more than the minimum time required to read out data corresponding to the entire capacity of the coding buffer memory from the coding buffer memory provided in the coding processing unit that performs the compression coding processing. A data transmission apparatus characterized by that.

Images